During surgery, particularly surgery in the abdominal cavity, it is necessary to employ surgical retractors to position organs to provide suitable access to the surgical site. Moreover, the required recovery period following surgery is often directly proportional to the size of the incision(s) made during surgery. Accordingly, laparoscopic surgery, which typically requires that only several small (1 cm.) incisions be made, is an increasingly utilized form of surgery because the recovery period is significantly reduced. Because the incisions made for laparoscopic are very small, manipulation of the surgical instruments, including retractors, at the surgical site is a very difficult and precise task. In particular, conventional surgical retractors are far too large to be passed through trocars used for laparoscopic surgery. In addition, retractors which may be narrow enough to be passed through a laparoscopic trocar often retract tissue in a direction extending from the tip of the retractor. However, it is often necessary to retract tissue in a number of different directions lateral to the body of the retractor.
These problems are not solved by known surgical instruments. For example, U.S. Pat. No. 4,909,789 discloses a forceps which act as a retractor for pushing aside tissue for improved observation. The device may be used with an endoscope, arthroscope or similar device. internally, three wires with rounded ends are contained within a barrel. The wires are spring biased in the retracted mode until pressure is applied to a plate, forcing the wires outwardly and diverging. A set screw may be adjusted to maintain the wire position. However, the retractors are forced out the end of the barrel, as opposed to the sides.
U.S. Pat. No. 4,654,028 discloses a tissue expander device. An elongated barrel houses a wire which emerges as three round ended wires at the end of the barrel. When energized, the wires expand in three dimensions thereby displacing soft tissue for improved visualization. This device is intended for use primarily for blood vessel graft surgery, as opposed to laparoscopic surgery. U.S. Pat. No. 1,878,671 discloses a dilator for drainage. A hollow shaft houses an elongated rod with an oblong head. When the rod is pushed in, the elongated head is displaced to the side so as to dilate surrounding tissue. Again, this device operates from the end of the barrel as opposed the side.
U.S. Pat. No. 4,655,219 discloses a multi-component grasping device. A plurality of wires with hooked ends are forced outward when engaged and close around the desired object when the wire is retracted. This device is not intended to be used as a retractor, and again, the wire ends are enjected from the tip of the barrel as opposed to the sides.
U.S. Pat. No. 4,705,041 discloses a dilator for the sphincter of oddi. A single rod is contained within a catheter and ends as a scissors-like mechanism. Retraction of the handle forces the central wire against the scissors mechanism forcing it open and expanding the region of interest. However, expansion occurs only in one plane perpendicular to the shaft, so tissue expansion is minimized.